Bruce Montague likes to maintain civility at his small midtown-Manhattan law office. But it's hard to be civil when your computer crashes, wiping out all the court dates you've just entered into your system. And that kind of thing was happening far too often last year as lawyers at Bruce Montague & Associates toggled between the Windows applications they used for research and the firm's seven-year-old case-management program, which ran on MS-DOS. "It slowed us down unbelievably," Montague says.

Lawyers also held the software in contempt because it couldn't easily sort the data to show, say, all the cases that had been settled or which court dates were approaching. Managing that information effectively has become increasingly important as Montague's firm, which specializes in personal-injury and commercial litigation, grows slowly but surely, increasing its caseload by 15% and adding one or two new employees each year. The firm recently moved to a larger space with a view of Manhattan's historic MetLife building, and Montague knew that aging case-management software would soon be a relic itself. But a replacement system would cost $10,000 -- more than the firm's return on the average broken-hip or collapsed-ceiling settlement.

Then one day in February, Montague's wife, Karen, mentioned that she'd heard about something called AppCity ( www.appcity.com). Headquartered a few blocks from Montague's new digs, AppCity is an application service provider, or ASP, a Web site that hosts software instead of requiring users to load it on their own computers. AppCity offers dozens of tools for business tasks like sales-force automation, employee management, and project tracking. Most compelling to Montague was AppCity's custom application function, the AppZapper.

Intrigued, Montague asked senior associate Craig Gardy to check out the site. Gardy, who holds a bachelor's degree in finance and is more comfortable with stock quotes than he is with software code, used AppZapper to create a unique case-management program for the law firm.

Gardy had a Microsoft Excel file full of such case information as file numbers, case names, dates when unsettled cases would expire, and a yes-or-no column indicating whether cases had been completed. He saved the file in CSV format, which meant the different categories were separated by commas, such as: case #123, Jane Doe vs. Slippery Sidewalk, 12/31/00, N (for "no, not completed"). Then he clicked on AppCity.com and downloaded AppPlayer, which runs AppCity programs. After opening AppPlayer (which can also be run online through a Web browser), Gardy clicked on the AppZapper icon. From there he opened the saved CSV file and selected the column headings for his data. That permitted Gardy to track cases without toggling to MS-DOS and crashing the computer.

Flexibility is the main reason AppCity targets the AppZapper to companies like Montague's, says company cofounder and CEO Mark Frankel. "Small and medium-sized businesses often have unique ways of doing things. They don't want to change their practices to match the software that's available," he says. "Here they can change the software to match their practices."

At Montague & Associates, corporate information stays on the firm's computers, but other AppCity users can move such data to AppCity's servers, then access it from any Web connection. (AppCity tools, initially free, are still available to individual users at no charge, but businesses must now pay for many of them.)

These days "we're 1,000 times more efficient," Montague says. Then, with the precision befitting a lawyer, he admits, "OK, maybe 500."